const pi = Math.PI;

module.exports=(radius) => {
  function diameter(){
    return 2 * radius;
  }
  function circumference(){
    return pi * 2 * radius;
  }
  function area(){
    return pi * radius * radius;
  }
  return {
    area,
    diameter,
    circumference
  };
};

console.log(module);
